Graphite's updated AI usage report puts six AI assistants at 76 billion sessions a month worldwide in September, up 37% from a year earlier, Search Engine Journal reports. Unlike the agency's March edition, which put AI sessions at 56% the size of search worldwide and 34% in the U.S., the new report makes no comparison with search engines. Graphite says the March edition likely undercounted Google's Android app, estimated at 11.8 billion monthly U.S. sessions, and that it "can no longer reliably compare" AI used for search with search engines. The counts are Similarweb estimates of web visits and mobile app sessions; Graphite sells SEO and AEO services, and Similarweb sells the data.
On referrals, Graphite says its data suggest AI accounts for less than 1% of website traffic on average. In U.S. traffic in the second quarter of 2026, organic search was 49 times the volume of AI referrals and paid search 8 times. AI referrals grew 92% year over year worldwide as of July and 75% in the U.S. ChatGPT sent 60% of AI referrals worldwide, followed by Gemini at 14% and Claude at 10%.
After what the report calls a plateau in late 2025, global sessions rose 19% from January through September 2026. ChatGPT sessions grew 24% and made up 58.9% of added sessions, Claude grew 1,901% and added 26%, and Perplexity fell 27%. Mobile accounted for 89% of global sessions in the third quarter.
Graphite cites anecdotal evidence that some AI-prompted visits are credited to direct or branded search, and says early numbers show branded search fairly flat year over year, with full results to come.